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EMU math department blog » Blog Archive » Oops! Error on the Problem Corner File Not Found – Eastern Mennonite University
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EMU math department blog

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Oops! Error on the Problem Corner

March 17th, 2009

In the Problem corner of our Winter 2008 Integram (http://www.emu.edu/math/integram/winter2008.html), we asked readers to find a collection of 21 distinct whole numbers where the sum of the reciprocals of those numbers was 21.  We received a number of correct solutions (thank you readers!).  We (okay, I) also felt compelled to include our own solution, because it cleverly used properties of Mersenne Primes and perfect numbers.  However, we (okay, I) were wrong!  Our (okay, my) proof used the “fact” that 2047 was prime.  However, as Dan Reinford (EMU, class of 1951) pointed out in private email correspondence, 2047 is the product of 23 and 89!  And so it is.  A perfectly beautiful proof just went poof.

You’ve got to admit, though, that 2047 certainly looks prime!  Anyway, thanks to Dan for pointing this out…certainly I feel a bit sheepish now, and I’ll make sure to be more careful with the solutions I provide to my own problems!

Owen

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File Not Found – Eastern Mennonite University
Eastern Mennonite University

A Christian university like no other - Eastern Mennonite University

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